Various remote premise-monitoring alarm systems are known from the prior art. For example, U.S. Pat. No. 5,745,849 shows a combination of a cordless telephone and a premise-monitoring alarm system which has a base unit, a cordless handset and one or more remote alarm detectors.
The alarm detectors can be generally either smoke detectors, motion detectors, or open-entry detectors. The base unit includes at least one interface for the public telephone network, and another interface for radio communication with the cordless handset. The base unit preferably also communicates with the remote alarm sensors across the same radio interface. The base unit includes telephone call circuitry to relay telephone calls between the public telephone network and the handset. The base unit also includes alarm processing circuitry to send an alarm warning to a central alarm-monitoring station in response to an alarm signal from a remote detector. The base unit has control circuitry that is configured such that if, during a telephone call, the base unit is given an alarm signal, the base unit will either (i) hang up the telephone call and call up the central alarm-monitoring station to give warning, or (ii) call up the central alarm-monitoring station on a second telephone line.
U.S. Pat. No. 6,271,752 shows a multi-access remote monitoring system for monitoring of a security surveillance area. The security surveillance area comprises a local computer system, a network interface, and a camera having a motion sensor. The local computer system is electronically connected via a camera adapter to the video camera so that video, sound, and motion sensor data can be transmitted from the camera to the local computer system, and instructions or other data can be transmitted from the local computer system to the camera. The local computer system is additionally connected to a computer network interface, which may be a modem, network card, or other communications hardware, used to connect to the communications network. The local computer system includes various components, including an audio/video coder/decoder, fixed storage means, operating system software, communications software, compression software, and application programming interface (API) software.
It is a common disadvantage of prior art remote monitoring systems that special, dedicated hardware is required at the site which is monitored. The present invention therefore aims to provide an improved remote monitoring method and system which enables to limit the hardware expenditure for the surveillance zone.